Nov 25, 2021

EPA & U.S. Ambassador Meet With Mexico to Address Transborder Pollution

Officials me to coordinate & plan actions to reduce pollution in the Tijuana River basin

EPA Administrator Michael S. Regan and U.S. Ambassador to Mexico Ken Salazar met with Mexico’s Secretariat of Foreign Affairs (SRE) Chief Officer for the North America Unit Roberto Velasco Álvarez; Ministry of Environment and Natural Resources (SEMARNAT) Head of International Affairs Miguel Ángel Zerón; Mexican National Water Commission (CONAGUA) Head of the General Technical Subdirectorate Dr. Humberto Marengo Mogollón; and other senior Mexican officials to coordinate and plan actions to reduce pollution in the Tijuana River basin.

The Administrator and Chief Officer Velasco Álvarez agreed to a Joint Statement committing to mechanisms for financing long term operation and maintenance of infrastructure projects in San Diego and Tijuana

“Transborder wastewater pollution in the Tijuana River has been a public health problem for the United States and Mexico for far too long,” Regan said. “Today’s meeting with leaders from Mexico’s government was extremely productive. It’s clear that the most effective solutions will require significant investment on both sides of the border, as well as binational cooperation to ensure lasting benefits for our communities.”


“We had very productive discussions on the need for increased investment in wastewater infrastructure to complement investments in the United States,” Salazar said. “Such infrastructure will benefit both countries and create opportunities for energy savings and wastewater reuse.”

In the Joint Statement, the U.S. and Mexico recognize the critical importance of addressing pollution for the benefit of citizens on both sides of the border and it recommits both countries to reducing transborder flows in the Tijuana River, the canyons, and our shared coastal waters.   

“For the Government of Mexico and for the Ministry of Environment and Natural Resources, it is of the highest priority to ensure access to a healthy environment, therefore, this type of collaboration clearly demonstrates that together with our determination and abilities, we can solve the challenges presented to us in this and other environmental issues,” said Miguel Ángel Zerón, Head of International Affairs in SEMARNAT.

“The projects considered in the EPA plan for the sanitation of the Tijuana River basin will significantly improve the quality of water in this river and on the beaches of both countries. CONAGUA, in accordance with the budget allocated to it, will provide its support for the completion of sanitation projects on the Mexican side that contribute to the fulfillment of that objective.” said Dr. Humberto Marengo Mogollón, Head of the General Technical Subdirectorate in CONAGUA.

The United States will proceed with a phased approach in building the various infrastructure projects that will address transborder pollution, because the overall cost exceeds the appropriated $300M under the United States-Mexico-Canada Agreement (USMCA). The phased approach gives flexibility to begin with priority projects that can be built the most quickly, then build additional projects as additional resources become available.

EPA is initiating environmental review of the following projects that have the highest potential to stem transborder pollution and improve water quality:

  • Expanding the existing South Bay International Wastewater Treatment Plant (ITP) owned and operated by the U.S. International Boundary and Water Commission (IBWC).
  • Diverting and treating Tijuana River water at a new facility adjacent to the existing ITP.
  • Conveying canyon flows to the expanded ITP.
  • Repairing portions of the collection system in Mexico to prevent sewage leaks.
  • Beneficially reusing treated wastewater instead of discharging it into the Tijuana River.
  • Installing a river trash boom.
  • Constructing a new San Antonio de los Buenos Treatment Plant in Tijuana.

As EPA completes its assessment of infrastructure options, a National Environmental Policy Act (NEPA) review will move forward to reduce potential negative environmental impacts from the projects that make up the comprehensive solution. This legally mandated review is needed before design and construction can begin.

To view a copy of the Joint Statement, visit:

For more information on the USMCA process, visit:


The Tijuana River carries untreated wastewater, trash, and sediment from Mexico across the border into the United States. In addition, polluted discharge into the Pacific Ocean from Tijuana’s wastewater treatment plant is carried northward during the summer, impacting beaches in southern San Diego County. The comprehensive infrastructure solution announced earlier this month is expected to substantially reduce impacts to the U.S.

In 2020, the USMCA was finalized to update and replace the North American Free Trade Agreement. The USMCA implementing legislation’s Section 821 directed EPA to coordinate with Eligible Public Entities to identify infrastructure solutions that address polluted transborder flows in the Tijuana River Watershed. The legislation also included an appropriation of $300 million for infrastructure projects in connection with wastewater facilities in the area of the United States–Mexico Border. These Eligible Public Entities include senior-level leaders from several cities in San Diego County (Imperial Beach, San Diego, Coronado, and Chula Vista), the County of San Diego, the State of California, and federal agencies.